Retinol is a well-known active ingredient in cosmetics. Retinol has proven to be a highly efficacious and cost-effective ingredient for treating skin over the last 20 years, but improvements in its activity and delivery, along with new product forms are always desirable.
U.S. Pat. No. 9,387,160 relates to oil-in-water compositions containing retinol that exhibit a controlled rate of release of retinol to the skin, thereby providing both increased retinol activity and decreased irritation. The composition comprises a non-polar emollient and a polar emollient. In one embodiment the composition comprises about 0.05 to about 0.5% by weight of retinol, propylene glycol stearyl ether (PPG stearyl ether), and isohexadecane, wherein the weight ratio of propylene glycol stearyl ether to isohexadecane is from about 75:25 to about 50:50.
Similarly, NEUTROGENA® Rapid Wrinkle Repair®, commercially available from Johnson & Johnson Consumer Inc., is an oil-in-water composition containing retinol, propylene glycol stearyl ether, and isohexadecane. It is used to fade the look of wrinkles in skin, smooth fine lines, improve skin texture, and brighten skin tone.
Applicants have now discovered that anhydrous or oil compositions containing retinol may also be formulated with a polar emollient and isohexadecane. However, surprisingly, in anhydrous compositions, the weight ratio of polar emollient to isohexadecane required to obtain good retinol activity but low irritation is the reverse of that needed in oil-in-water emulsions, such as those described in the '160 patent. Specifically, in anhydrous compositions, the weight ratio of polar emollient to isohexadecane required to obtain high retinol activity-to-low irritation levels is 1:1 or lower, for example about 1:2 to less than about 1:1.